1. Field of the Invention
The present invention relates to an organic thin film transistor, a method of manufacturing the same, and an organic light emitting display device having the same, and more particularly, to an organic thin film transistor that can prevent damage to source and drain electrodes when an organic semiconductor is patterned, a method of manufacturing the same, and an organic light emitting display device having the same.
2. Description of the Related Technology
Thin film transistors are used in flat display devices such as liquid crystal display devices, and organic light emitting display devices, as switching devices to control the operation of each pixel or driving devices to drive each pixel.
The thin film transistor includes a semiconductor layer having source and drain electrodes separated from each other, a channel region formed between the source and the drain electrodes, and a gate electrode insulated from the source and drain electrodes and the semiconductor layer.
Thin film transistors having the above structure are arranged in an array, each acting as an independent switching device. To prevent cross-talk between adjacent thin film transistors, the semiconductor layer may be patterned. In a conventional silicon thin film transistor, a semiconductor layer formed of silicon is patterned by photolithography.
Recent studies into flexible display devices have attempted to use plastic substrates instead of conventional glass substrates. However, since the plastic substrate cannot be processed at a high temperature, it is difficult to use the conventional silicon substrate.
Accordingly, methods to form plastic substrates at a low temperature have been proposed. In particular, studies with regards to organic thin film transistors that can be processed at a low temperature, that is, thin film transistors in which a semiconductor layer is formed of an organic material, have been actively conducted. However, in the case of the organic thin film transistor, the semiconductor layer cannot be patterned by conventional photolithography. That is, when the conventional processes of wet or dry etching and photolithography are mixed, the organic semiconductor layer can be damaged, thereby degrading the thin film transistor.